Loss of Power Steering Due to Leaking Steering Rack on Mercedes-Benz ML350

Problem Description and Possible Solution

It is not uncommon for the power steering rack to develop a fluid leak requiring replacement of the rack assembly. Loss of power steering fluid may also cause an abnormal noise and damage to the power steering pump.

Problem Data
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Average mileage: 89,444 (31,500–200,000)
7 model years affected: 2003, 2004, 2005, 2009, more2010, 2011, 2013
88 people reported this problem
Viewing 1 - 20 of 45 comments
Had to replace the power steering at 59000 miles. Just learned that there was a recall. I was never notified of this by the dealer since I did not own the vehicle when I they sent out notices. So aggravated and seeking recourse.
ML350 made winding sound when putting vehicle in motion. Sound would go away as vehicle sped up, but would return when slowing down at lights or to make turns. Discovered small leak of power steering fluid. First look it appears from the hose and not reservoir.
My car has been leaking power steering fluid since about 110,000 miles. I now constantly replace the fluid on a regular basis rather than paying the $1500 repair cost.
Just learned that my steering rack is leaking and needs to be replaced. $1500 for the parts plus $600 labor. Called Mercedes, they told me there is no recall on that.
Steering completely out at slow speed. VERY hard to steer. Power steering pump and hose replaced. $1600
Noticed leakage on garage floor. Placed drip pan underneath and determined that leakage was power steering fluid. Took to dealer (7th MB, always take to dealer-better results). Dealer said probably steering rack. Options: 1) replace rack, ~$3,000 or 2) install "seal replacement kit", ~1,500. Plan to keep vehicle as has been bulletproof till now. Mech found leak where P/S fluid reservoir attaches to pump and resealed it. Brought home, cleaned garage floor and parked truck. Next day noticed more leakage. Back to dealer. Now mech finds leak at the input shaft on the steering rack, same options. Upon questioning mech says the dealer (small dealership) has done this replacement (option 2) several times and has had no come-back on it so I went with that. Job is labor intensive in that to remove steering rack, the front differential and a support member have to be removed and replaced. Obvious MB knows of this issue but haven't been able to find any MB tech bulletin on it.
Update: Vehicle now has 173,000 miles on it. I had the seals replaced in the steering rack. About $30.00 worth of parts but seriously labor intensive-have to remove front differential and other big stuff. Total bill, including 4-wheel realignment was $1,738. Have had no further problem with that in last 43K miles. Did have big issue with torque converter not locking up when it should. Dealer replaced it and flushed transmission about 20K miles ago and no further problem. That burned up $3000.00. Still love the vehicle. Bought new Porsche Cayenne diesel for long road trips, but the ML-350 just keeps on chugging.
Recently my power steering fluid start leaking at the connection of the column and the rack. I replaced it my self. Cost $1000 + between remanufacting parts and rental. A quick tip to do that job fast is to disconnect the 2 front axles and drop slowly on the front differentiel. Have a pan for the oil too
This is my 4th time replacing the power steering pump, rack n pinions.. Whinning leaking and tightness are the repetitive issues.
Car started leaking fluid . Dealer will replace rack and pinion for$2100 . I got a rebuilt rack and pinion with lifetime warrantee for $500 at Phoenix Rack and Pinion. They remove and replace also if needed. Collay
Leaking power steering fluid has lead to a failure in the power steering rack control head and bushings.
Steering became really "stiff". When turning the steering wheel either way, it was hard to steer as if power steering went out. Took it to a mechanic - Rack and pump replacement - $3500! OUCH!!!